There are very different kinds of LDs, operating in very different regimes of optical output power, wavelength, bandwidth, and other properties: 1  Small edge-emitting LDs generate between a few milliwatts and up to roughly half a watt of output power in a beam with high beam quality.
The Washington state sales tax rate is 6.5% , and the average WA sales tax after local surtaxes is 8.89% 1  . Groceries and prescription drugs are exempt from the Washington sales tax. 2  Counties and cities can charge an additional local sales tax of up to 3.1%, for a maximum possible combined sales tax of 9.6%.
Washington State does not have a state income tax. Also, according to their website, they do not have a separate tax on gambling winnings. Looks as if you will not have to worry about any state tax on the $3900.